/Engine/Source/Runtime/TypedElementFramework/Public/Elements/Framework/TypedElementList.h
Add the given element owner to this element list, if it isn't already in the list.
True if the element owner was added, false if it is already in the list.
template<typename ElementDataType> bool Add ( const [TTypedElementOwner](API\Runtime\TypedElementFramework\Elements\Framework\TTypedElementOwner)< ElementDataType > & InElementOwner )